I enjoy reading these for the historical aspect of this. Such as "Handloading Ammunition" by J R Mattern, published in 1926. I would certainly never load using the data in them but the prose part is of interest. Any other early recommended titles perhaps going back as far as the 19th Century?
I should mention I stumbled across this at a flea market many years ago.
I also already have Phil Sharpe's book.